Pythagorean Astronomy

Over the course of the next month, we'll see the arrival at Mars of not one, not two, but three spacecraft: Nasa’s Perseverance Rover, with its little helicopter Ingenuity; the Chinese Space Agency's Tianwen-1 mission, which comprises an orbiting spacecraft, a landing platform and a rover; and the UAE's Hope mission, which is an orbiting spacecraft. In this episode we'll be hearing about the upcoming missions to Mars, as a bit of insight into the Chinese Space Programme. Of course, a sensible question is: why all the interest in Mars? It's a dead planet now – or certainly pretty dead – but perhaps that wasn’t always the way. To find out more I spoke to Dr Peter Fawden, whose expertise is the geological history of Mars. Peter is based at the Open University where he works on the imaging cameras of a future mission: the Rosalind Franklin Rover, due to launch in a couple of years. On Earth we can dig up rocks, or go to a cliff, perhaps by a beach, and look at the layers of rock, studying the order in which the